The present invention relates to motion transmitting devices in general, and more particularly to improvements in elongated flexible motion transmitting devices (hereinafter called chains for short). Still more particularly, the invention relates to improvements in chains (such as endless link chains) which can be utilized with advantage to transmit torque between pulleys or sheaves, such as adjustable pulleys forming part of continuously variable (CVT) and analogous transmissions. The invention also relates to improvements in methods of making link chains as well as to transmissions which employ the improved chains.
Chains of the character to which the present invention pertains are disclosed, for example, in German patents Nos. 44 15 838 and 35 26 062. The patented chains comprise longitudinally extending links which are articulately connected to each other by transversely extending pintles or bolts (also called rocker elements). The end portions of the bolts extend to or beyond the lateral sides of the assembled chain and are provided with abutments serving to prevent accidental dismantling of the assembled chain and/or as a means for contacting the flanges of pulleys in the transmissions in which the patented chains are put to use, i.e., at those locations where the bolts and the neighboring links are most likely to become partially or fully separated from each other. As a rule, each bolt carries an abutment at each of its ends, i.e., at both lateral sides of the assembled chain. Reliable retention of all constituents of a link chain in fully assembled condition is highly desirable because the disengagement of one or more links from the neghboring bolts reduces the effectiveness of the chain and can entail total destruction of the chain, a malfunctioning or a complete breakdown of the transmission, e.g., failure of the transmission to transmit torque between the driving and driven pulleys one of which receives torque from a prime mover and the other of which transmits torque (directly or indirectly) to the driven axles in the power train of a motor vehicle. This can result in injuries or inconvenience to the occupant(s) of the motor vehicles, for example, if a breakdown takes place at a location which is remote from a service station.
On the other hand, the provision of plural abutments of adequate sturdiness, size and shape on each bolt of a link chain contributes significantly to the cost of conventional link chains, not only because of the expenses involved in connection with the making of the chain but also as concerns the cost of the materials which are required for the making of the abutments and/or for attachment of separately produced abutments to the end portions of the respective bolts.